Zonnon

module Philosophers;

const
    NumPhilosophers = 5;

activity Philosopher(id: integer; left, right: Fork);
begin
    loop
        (* thinking *)
        writeln("Philosopher ", id, " is thinking");
        delay(random(1000));
        writeln("Philosopher ", id, " is hungry");
        (* hungry *)
        accept get ->
            left.get;
            right.get;
            (* eating *)
            writeln("Philosopher ", id, " is eating");
            delay(random(1000));
            left.put;
            right.put;
    end
end Philosopher;

activity Fork;
var
    taken: boolean;
begin
    taken := false;
    loop
        select
            when {~taken} accept get ->
                taken := true
        []
            when {taken} accept put ->
                taken := false
        end
    end
end Fork;

var
    i: integer;
    forks: array NumPhilosophers of Fork;
    philosophers: array NumPhilosophers of Philosopher;

begin
    for i := 0 to NumPhilosophers-1 do
        new(forks[i])
    end;
    for i := 0 to NumPhilosophers-1 do
        new(philosophers[i], i, forks[i], forks[(i+1) mod NumPhilosophers])
    end
end Philosophers.